Cameras using a solid state image sensor such as a charge coupled device (CCD) and a complementary metal oxide semiconductor (CMOS) image sensor have been rapidly distributed. To increase resolution of a camera, a degree of pixel integration of a solid state image sensor is increased. Also, the size and weight of a camera is being reduced through improvement of performance of a lens optical system included in a camera.
In a general lens optical system of a camera, a large number of lenses are used to secure performance of the lens optical system, e.g., to secure a large angle of view and to correct aberration. However, when the lens optical system includes many lenses, it may be difficult to make a compact and lightweight camera. There is a demand to develop a compact lens optical system having a relatively wide angle of view and being able to easily correct aberration.
Recently, as iris recognition technology has drawn attention as the next generation technology for authentication and security, there is a demand to develop a lens optical system for an iris recognition camera. In other words, there is a demand to improve performance of an iris recognition lens optical system and to secure a wide viewing angle thereof.